Playback devices for optical memory disks, in the form of compact disc players, are already known. German Patent Application No. 196 42 343, not pre-published, describes a compact disc drive that has a motor for rotation of a compact disc clamped between two plates. In addition, a read head is mounted on a transport mechanism that moves the read head radially over the compact disc.
The electrical device according to the present invention has, in contrast, the advantage that the supply voltage can be adapted in each case to the currently highest voltage demand, so that power losses are avoided. The use of the same supply voltage for the means also results in an elimination of additional voltage supply units and thus a savings in material, space, and cost.
Minimizing the dissipation power also results in the advantage that less space is required for cooling surfaces to discharge the dissipation power.
It is advantageous that provision is made for a playback mode in which the supply voltage does not fall below a first predefined value. As a result, when an optical storage disk is played back, only the energy necessary for that purpose is consumed, and no unnecessary dissipation power is produced.
A further advantage is the fact that a vibration mode is provided, in which the supply voltage does not fall below a second predefined value. This makes possible a higher control loop gain during playback in the presence of vibration, so that vibration-related interference in the scanning of an optical memory disk by the scanning unit can be better compensated for.
It is furthermore advantageous that the supply voltage is set by a switching power supply. As a result, no additional losses occur when the voltage is lower than the full available supply voltage.
It is also advantageous that an analysis circuit is present which ascertains the highest currently required voltage demand of the means, and as a function of that voltage demand delivers a control signal to set the supply voltage necessary therefor. The result is to make possible automatic adaptation of the supply voltage to the currently highest voltage demand of the means, so that the electrical device is automatically operated at every point in time with the lowest possible dissipation power.
A further advantage lies in the fact that a means for feeding in and/or ejecting an optical memory disk is provided, to which the supply voltage is conveyed; and that the supply voltage is set as a function of the voltage demand of that means. The functionality of the voltage supply system is thereby further enhanced, and the space and material for an additional power supply for feeding in or ejecting an optical memory disk are eliminated.
A further advantage is the fact that the supply voltage is set as a function of the voltage demand for feeding in and/or ejecting the optical memory disk, so that a higher supply voltage necessary for that purpose also needs to be made available only for the infeed or ejection operation, thus economizing on dissipation power.
A further advantage is the fact that an infeed/eject mode for feeding in or ejecting an optical memory disk is provided, in which the supply voltage does not fall below a third predefined value. The result is to ensure that the energy necessary for feeding in or ejecting the optical memory disk is made available when necessary.